Not human inventiveness but God’s word alone (Josh. 8:30-35)

“In verse 31 we are told that Joshua built this altar ‘as it is written in the Book of the Law of Moses: ‘an altar of whole stones over which no man has wielded an iron tool.’ We noted previously that this law, found in Exodus 20:25, taught the people that their approach to God was not to be defiled by the work of their own hands…

The abiding principle is that man is not to seek to ‘enhance’ his approach to God by adding touches of his own to the Lord’s perfect provision. This is made clear by the close connection between the original statement of this command with the warning against idolatry (see Exodus 20: 23-25). Once again, we find God warning His people that the impositions of their own ingenuity in worship will ultimately lead them to worship the work of their own hands.” (Comin, 55-56)